Question

我正在制作一个应用程序，它将从SD卡中获取歌曲填写listview。但由于某种原因，它不会填充和显示空白片段。你能帮忙解决造成这种情况的原因吗？问题。谢谢。

bellasongs.java

public class BellaSongs extends ListFragment {

    private ArrayList<ModelBellaSongs> BellaSongList;
    private ListView Bellasongviews;
    Context context;

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootview = inflater.inflate(R.layout.bella_songs, container, false);
        Bellasongviews = (ListView)rootview.findViewById(android.R.id.list);

        BellaSongList = new ArrayList<ModelBellaSongs>();
        return rootview;
    }

    public void getBellaSongList() {
        ContentResolver musicResolver = context.getContentResolver();
        Uri musicUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
        Cursor musicCursor = musicResolver.query(musicUri, null, null, null, null);

        if (musicCursor != null && musicCursor.moveToFirst()) {
            int titlecolumn = musicCursor.getColumnIndex(MediaStore.Audio.Media.TITLE);
            int idcolumn = musicCursor.getColumnIndex(MediaStore.Audio.Media._ID);
            int artistcolumn = musicCursor.getColumnIndex(MediaStore.Audio.Media.ARTIST);

            do {
                long thisId = musicCursor.getLong(idcolumn);
                String thistitle = musicCursor.getString(titlecolumn);
                String thisartist = musicCursor.getString(artistcolumn);
                BellaSongList.add(new ModelBellaSongs(thisId, thistitle, thisartist));
            } while (musicCursor.moveToNext());
        }
        getBellaSongList();

        Collections.sort(BellaSongList, new Comparator<ModelBellaSongs>() {
            @Override
            public int compare(ModelBellaSongs a, ModelBellaSongs b) {
                return a.getTitle().compareTo(b.getTitle());
            }
        });

        BellaSongsAdapter bellasongsadapter = new BellaSongsAdapter(getActivity(),BellaSongList);
            Bellasongviews.setAdapter(bellasongsadapter);
    }
}

adapter.java

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">


<ListView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@android:id/list"
    android:layout_gravity="center_vertical"
    android:layout_weight="1" />

 </LinearLayout>

bellasongsadapter.java

public class BellaSongsAdapter extends BaseAdapter {

    private ArrayList<ModelBellaSongs> bellasongs;
    private LayoutInflater songdetails;

    public BellaSongsAdapter(Context c, ArrayList<ModelBellaSongs>thesongs){
        bellasongs = thesongs;
        songdetails = LayoutInflater.from(c);
    }

    @Override
    public int getCount() {
        return bellasongs.size();
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LinearLayout songLayout=(LinearLayout)songdetails.inflate(R.layout.singlelist_item,parent,false);
        TextView titleview=(TextView)songLayout.findViewById(R.id.text_song_name);
        TextView artistview=(TextView)songLayout.findViewById(R.id.text_artist_name);

        ModelBellaSongs currentsongs = bellasongs.get(position);
        titleview.setText(currentsongs.getTitle());
        artistview.setText(currentsongs.getArtist());
        songLayout.setTag(position);

        return songLayout;
    }
}

Answer 1

我认为您的身份证明不正确

Bellasongviews = (ListView)rootview.findViewById(android.R.id.list);

请确保此android.R.id.list ID正确无误，应从R.id.yourId

开始

此处不要导入android.R此处导入您的项目R。

检查您的XML布局文件的ID，或者在您的问题中将其粘贴到此处。

Answer 2

查看你的代码，我看到方法getBellaSingList（）。这个方法正在检索数据，甚至反复调用自己，但它不会在onCreateView()内调用。从技术上讲 - 您没有填充数据集。您需要在初始化视图时调用它 - 并且请验证此方法的逻辑。

Listview不会在片段中填充sd卡中的歌曲

2 个答案: